Yarn clamping and cutting attachment for circular knitting machines

ABSTRACT

An auxiliary clamp to hold an elastic yarn in combination with a conventional yarn cutting and holding mechanism of the type used on a circular hosiery knitting machine and in which pneumatic means is used to hold the yarns. While the pneumatic means is capable of holding the ends of non-elastic yarns it is not capable of holding the ends of elastic yarns. The clamp is selfacting and provides a wedge shaped opening to hold the elastic yarn, the opening being defined by a flat surface of the conventional mechanism and by a straight edge of a plate member disposed at an angle to the flat surface. The elastic yarn is forced into the wedge shaped opening of the clamp by the movement of the inactivated elastic yarn itself as the last needle taking the same moves around the machine.

United States Patent 1 1 Conti 1 1 Dec, 11, 1973 YARN CLAMPING AND CUTTING ATTACHMENT FOR CIRCULAR KNITTING MACHINES [75] Inventor: I Paolo Conti, Florence, Italy [73] Assignee: G. Billi & C. S.p.A., Firenze, Italy [22] Filed: Dec. 7, 1970 [21] Appl. No.: 95,585

[30] Foreign Application Priority Data Dec. 12, 1969 Italy 4885 A/69 [52] US. Cl. 66/140 R, 66/140 S [51] Int. Cl D041) 15/61 [58] Field of Search 66/134, 140 S, 145, 66/145 S, 140 R, 145 B; 57/87; 112/253 [56] References Cited UNITED STATES PATENTS 1,482,004 1/1924 Garey 57/87 926,629 6/1909 West.... 66/145 R 965,351 7/1910 West 66/145 R 2,559,327 7/1951 St. Pierre 66/145 R 3,208,240 9/1965 Morehead.... 66/145 S X 3,367,146 2/1968 Allred 66/134 3,379,036 4/1968 Farmer 66/145 R 3,494,151 2/1970 Baker et al. 66/140 5 FOREIGN PATENTS OR APPLICATIONS 1,542,833 9/1968 France 66/145 3 [57] ABSTRACT An auxiliary clamp to hold an elastic yarn in combination with a conventional yarn cutting and holding mechanism of the type used on a circular hosiery knitting machine and in which pneumatic means is used to hold the yarns. While the pneumatic means is capable of holding the ends of non-elastic yarns it is not capable of holding the ends of elastic yarns. The clamp is self-acting and provides a wedge shaped opening to hold the elastic yarn, the opening being defined by a flat surface of the conventional mechanism and by a straight edge of a plate member disposed at an angle to the flat surface. The elastic yarn is forced into the wedge shapedopening of the clamp by the movement of the inactivated elastic yarn itself as the last needle taking the same moves around the machine.

4 Claims, 4 Drawing lF igures PM'ENIEBUEBI 1 ms INV'ENT'OR PAOLO OQNTi ATT RNEY YARN CLAMPING AND CUTTING ATTACHMENT FOR CIRCULAR KNITTING MACHINES THE INVENTION The present invention relates generally to the art of knitting and more particularly to yarn cutting and hold ing means for circular knitting machines wherein an auxiliary clamp is provided to hold elastic yarn.

In circular hosiery knitting machines, particularly those used for the manufacture of ladies hosiery, it is the practice to use yarn cutting and holding means of the type in which the cut ends of the yarns being used in the machine are held by pneumatic means. While the pneumatic holding means is sufficient to maintain the ends of the usual non-elastic yarns in proper position for feeding to the needles, it is not capable of holding the end of elastic yarn in tensioned condition and in proper position for feeding to the needles.

It is accordingly the principal object of the present invention to provide an auxiliary clamp, in combination with the conventional yarn cutting and holding means, to hold the cut end of the elastic yarn so that it remains tensioned and in proper position to be fed to the needles of the machine.

It is also an object of the present invention to provide a self-acting auxiliary clamp to hold the cut end of the elastic yarn wherein the clamp is provided with a wedge shaped opening and wherein the elastic yarn, upon being inactivated, is forced into clamped position in said opening by the movement of the elastic yarn itself as it is moved around the machine by the last needle taking the elastic yarn.

With the above and other objects in view which will become apparent from the following detailed description of the illustrative embodiment of the invention shown in the accompanying drawings, the invention resides in the novel elements, features of construction and co-operation of parts, as hereinafter more particularly pointed out in the claims.

IN THE DRAWINGS FIG. I is a side elevational view, partly in section, showing a conventional yarn cutting and holding mechanism disposed upon the dial cap of a circular knitting hoisery machine and also showing the auxiliary elastic yarn clamp of the present invention in combination therewith.

FIG. 2 is a plan view of the apparatus shown in FIG. 1.

FIG. 3 is an enlarged view of the elastic yarn clamp shown in FIG. 1.

FIG. 4 is a cross-sectional view of FIG. 3 as taken on line IV-IV thereof.

Circular hoisery knitting machines, particularly those used for the production of ladies hoisery, are generally provided with a revolving transfer dial, as shown at 1 in the drawings, and within which a circular series of radially movable transfer hooks 3 are disposed. The dial is positioned above a revolving cylinder 7 which is provided with slots within which a circular series of needles are vertically movable. The transfer hooks 3 are adapted to co-operate with the needles 5 in the hosiery formation.

Arranged upon and rotating with the dial 1 is an annular ratchet cutting ring 9 upon which the idled yarns are engaged and are cut. The yarns are fed to the needles from a plurality of yarn guides at a plurality of places or feeds around the machine and one such group of yarn guides is indicated at 111. The yarn guides are lowered and raised to place their yarns into and out of feeding positions. A dial cap or cam plate for operating the transfer hooks is shown at 13 and is provided with a generally flat upper surface. Disposed above the plate 13 is a circularly shaped generally flat cup-like member 15 with the open side thereof facing and spaced from the plate 13 thereby to provide one or more narrow peripheral slit-like openings l7 therebetween. The idled yarns are adapted to be drawn through the openings 17 as they are moved around the machine by the last of the needles knitting the same. The interior of the cup 15 is connected to a diametrically disposed spaced pair of exhaust tubes l9, 19, which are operatively related to a suitable exhaust fan or vacuum pump whereby suction is created internally of the plate 13 and cup 15. The suction draws air through the slits I7 and draws the idled yarns therethrough.

A pair of oppositely disposed cutting members 21, 21, are arranged on the cup 15 to co-operate with the cutting ring 9, and the members 21, 21, are provided with cutting blades 21A, 218, to press against the ring 9 to cut any yarns carried thereby around the machine. As each yarn guide llll is raised out of feeding position to idle its yarn, the last needle to have taken the yarn carries it around the machine in the direction of the arrow ft. The yarn, as it is so carried around the machine, is caught in the teeth of the ring 9, moves through the slit 17 to a position between the plate 13 and cup 115, and is cut by the blades 21A, 21B. Thereafter, the cut end portions of the idled yarns are drawn into the tubes 119 and are pneumatically held there by suction until they are once again fed to the needles of the machine.

The pneumatic holding action in the tubes 19 is sufficient to retain the terminal portions of the non-elastic yarns until they are reintroduced to the needles, however, it is not sufficient to effectively hold the terminal portions of elastic yarns. As elastic yarn, such as shown at F, is fed to the needles in a tensioned and elongated condition as the result of tension applied to the yarn between its yarn finger HA and its source of supply. The yarn finger MA is the first of the yarn fingers reached by the rotating needles of the machine. After the idled yarn F has been moved around the machine and cut by blade 2TB, its free end portion will be considerably shortened as the tension in the yarn is released. The elastic yarn cut end cannot be held pneumatically in the tube 119 and tends to work its way out of the slit l7 and may even remove itself from the yarn finger llllA. Obviously, such a condition of the free end portion of the elastic yarn F is not desirable as it is not then in condition for the yarn to be successfully reintroduced to the needles of the machine when the yarn finger MA is placed in active position.

Accordingly, by the present invention, an auxiliary clamp is provided for the terminal portion of each elastic yarn F, at a point spaced from its finger llllA, so that it is maintained in proper condition to be taken by the needles. Each elastic yarn clamp comprises a vertically disposed relatively flat member 25 secured to a correspondingly flat portion of the outside of cup 15 adjacent to the yarn intake slot I7, at a point just ahead of the yarn finger MA, in the direction of the cylinder rotation. Clamp 25 is provided with a straight lower edge 25A of which one end is in contact with, or is very nearly in contact with, the upper fiat surface of plate 13, while the remainder of the edge 25A is inclined with respect to the surface of plate 13 thereby to provide a wedge shaped opening therebetween. The clamp 25 is secured to the member 15 by means of a screw 27 passing through an elongated slot in the clamp 25 and into threaded engagement with the member 15. It will be understood that the angle of inclination of clamp 25, as well as its circumferential position, may be adjusted as required and that a set screw may be used for this purpose. Between the surface of plate 13 and the lower inclined'edge 25A of the clamp 25, there is defined a wedge shaped opening having inclined and convergent edges, one toward the other, in the direction in which the yarn F moves into the said opening, as shown by the arrow f3 in FIG. 3. As the last needle taking the yarn F moves around the machine, in the direction of the arrow F1 (counterclockwise in FIG. 2), the elastic yarn extending from guide 11A to the last needle, is caught in the toothed ring 9 which rotates in a counterclockwise direction with the needle cylinder and the yarn F moves into the wedge-shaped opening through the wide portion of the slot 17 as the rotating ring 9 and said last needle carry the yarn circumferentially around the needle cylinder to cutting element 218. The yarn F as sumes the position shown in the dot dash lines of FIG. 2 around vertically extending spaced pins 23 and 23A between plate 13 and cup 15. After the elastic yarn F has been carried to the cutting blade 21B by the ring 9 and by the last needle to take the same, it is cut by the blade 21B, As the yarn F is first forced between plate 13 and clamp edge 25A, it first assumes an initial path F1 between the yarn guide 11A and the first pin 23A thereby forming an angle a of less than 90.between the plane of the face of the clamp and the length of yarn F1. This permits the yarn to move in one direction only through the clamp. The elastic yarn then slides further into the clamp in the direction off3 as a result of the forces working upon it and is locked in the clamp to extend along the path marked F between pin 23A and the yarn finger 11A, when the yarn is cut by the blade 21B. The cut terminal portion of the elastic yarn is shortened as the tension therein is released by the cutting, however, due to the arrangement of the clamp 25 opposite cutting element 218 and adjacent yarn finger 11A, such shortening takes place only between the clamp 25 and the end of the yarn cut at cutting element 21B. The cut and shortened free end of the elastic yarn remains inside the slit 17. The elastic yarn extending between the clamped portion thereof in said last-named clamp 25 and the yarn finger 11A, as well as the yarn between the yarn finger 11A and its zone of applied tension, remains in the tensioned state and in proper position to be taken by the needles when the finger 11A is lowered to yarn feeding position whereupon the elastic yarn is pulled from the clamp.

The other yarns used in the machine, including stretch yarns which have some degree of resiliency and which are of less diameter than the relatively larger diameter elastic yarn, although they are inserted into and out of clamp 25 during normal operation, they are not interfered with by the action of clamp 25 on the elastic yarn F.

What I claim is:

1. In combination with a circular hoisery knitting machine of the type having a yarn feeding device with fingers adapted to be raised and lowered to feed their respective out of operative relationship with the needles of said machine, and a cutting device spaced peripherally around the machine from said yarn feeding device, means for carrying an inactivated elastic yarn from the last needle taking the same to said cutting device, a clamping apparatus in the yarn path between said yarn feeding device and said cutting device, said clamping apparatus comprising a pair of rigidly disposed cooperating edges defining a wedge-shaped slot therebetween, the widest part of said wedge-shaped slot being spaced further from said yarn feeding device than the narrow portion of the wedge-shaped slot, whereby an inactivated tensioned elastic yarn is carried into said slot and becomes pinched between said cooperating rigidly disposed edges after the yarn is severed, thereby retaining the tension in said yarn between the clamp and the feed finger and only the yarn portion between said clamping device and said cutting device becomes relaxed and shortened.

2. The combination according to claim 1 wherein said clamping apparatus is so arranged with respect to the yarn feeding finger carrying the elastic yarn and said cutting device that the angle between the vertical plane of said wedge-shaped slot and the yarn path therethrough is always less than 3. The combination according to claim 2 wherein one of said pair of cooperating edges comprises a flat surface along which the inactivated yarns slide as they are carried to said cutting device, and the other of said pair of cooperating edges comprises a plate positioned normal to said flat surface and having a lower edge inclined with respect to said flat surface from a point spaced from said flat surface to a point in engagement with said flat surface thereby forming said wedgeshaped slot, whereby the inactivated elastic yarn enters said slot at the widest point and is moved along said slot to a point where said edge members pinch against and hold said yarn when it is cut.

4. The combination according to claim 3 wherein the elastic yarn is fed by the yarn finger in said yarn feeding device which is first reached by the rotating needles of the machine. 

1. In combination with a circular hoisery knitting machine of the type having a yarn feeding device with fingers adapted to be raised and lowered to feed their respective out of operative relationship with the needles of said machine, and a cutting device spaced peripherally around the machine from said yarn feeding device, means for carrying an inactivated elastic yarn from the last needle taking the same to said cutting device, a clamping apparatus in the yarn path between said yarn feeding device and said cutting device, said clamping apparatus comprising a pair of rigidly disposed cooperating edges defining a wedge-shaped slot therebetween, the widest part of said wedgeshaped slot being spaced further from said yarn feeding device than the narrow portion of the wedge-shaped slot, whereby an inactivated tensioned elastic yarn is carried into said slot and becomes pinched between said cooperating rigidly disposed edges after the yarn is severed, thereby retaining the tension in said yarn between the clamp and the feed finger and only the yarn portion between said clamping device and said cutting device becomes relaxed and shortened.
 2. The combination according to claim 1 wherein said clamping apparatus is so arranged with respect to the yarn feeding finger carrying the elastic yarn and said cutting device that the angle between the vertical plane of said wedge-shaped slot and the yarn path therethrough is always less than 90*.
 3. The combination according to claim 2 wherein one of said pair of cooperating edges comprises a flat surface along which the inactivated yarns slide as they are carried to said cutting device, and the other of said pair of cooperating edges comprises a plate positioned normal to said flat surface and having a lower edge inclined with respect to said flat surface from a point spaced from said flat surface to a point in engagement with said flat surface thereby forming said wedge-shaped slot, whereby the inactivated elastic yarn enters said slot at the widest point and is moved along said slot to a point where said edge members pinch against and hold said yarn when it is cut.
 4. The combination according to claim 3 wherein the elastic yarn is fed by the yarn finger in said yarn feeding device which is first reached by the rotating needles of the machine. 